Income Taxes 6 (Details) In Millions, unless otherwise specified	12 Months Ended		1 Months Ended	12 Months Ended
	Mar. 31, 2015 USD ($)	Mar. 31, 2014 USD ($)	Nov. 30, 2013 Brazilian Tax Authority BRL	Mar. 31, 2015 Brazilian Tax Authority USD ($)
Income Tax Disclosure [Abstract]
Total deferred tax assets, net of valuation allowance	$ 519	$ 572
U.S. federal, state and foreign net operating loss carryforwards	542	672
Net operating loss carryforwards subject to expiration	412
Net operating loss carryforwards expiration period	between 2015 and 2034
Net operating loss carryforwards not subject to expiration	130
Change in valuation allowance	(2)	4
Unremitted earnings of foreign subsidiaries	2,759	2,349
Determination of tax on unremitted foreign earnings is not practicable	It is not practicable to determine the amount of tax associated with such unremitted earnings.
Liability for uncertain tax positions, Gross	162	202
Liability for uncertain tax positions, Current	3	0
Deferred tax assets related to uncertain tax positions	16	17
Unrecognized tax benefits that would affect effective tax rate	109	127
Amount of interest and penalties accrued	28	32
Decrease in amount of interest and penalties	(4)	(72)
Period of unrecognized tax benefit adjustment (in months)	12 months
Income Tax Examination [Line Items]
Tax assessment including interest and penalties			211	$ 66